Consider, for a moment, the electric wire, a ubiquitous technology that is very easy to forget. Coiled in our devices, wrapped around our walls, strung along our streets, millions of tons of thin metal wires do the job of electrifying the world. But their work is benign, and so naturalistic that it doesn’t really feel like technology at all. Wires move electrons simply because that’s what metals do when current is supplied to them: they conduct.
But there is always room for improvement. Metals conduct electricity because they contain free electrons that are not attached to particular atoms. The more electrons flow and the faster they go, the better a metal conducts. So to improve that conductivity — crucial for preserving the energy produced in a power plant or stored in a battery — materials scientists typically look for more perfect atomic arrangements. Their main purpose is purity: to remove bits of foreign material or imperfections that interrupt the flow. The more a hunk of gold is gold, the more copper wire is copper, the better it will conduct. Everything else just gets in the way.
“If you want something really highly conductive, you just have to go pure,” said Keerti Kappagantula, a materials scientist at the Pacific Northwest National Lab. That is why she finds her own research rather ‘shaky’. Her goal is to make metals more conductive by making them fewer pure. She will take a metal like aluminum and add additives like graphene or carbon nanotubes, creating an alloy. Do that the right way, Kappagantula discovered, and the extra material can have a weird effect: It can push the metal past its theoretical limit of conductivity.
In this case, it’s about making aluminum that can compete with copper in electrical appliances — a metal that’s nearly twice as conductive, but also costs about twice as much. Aluminum has advantages: it is much lighter than copper. And as the most abundant metal in the Earth’s crust — a thousand times more than copper — it’s also cheaper and easier to dig up.
On the other hand, copper is becoming increasingly difficult to obtain as the world moves towards greener energy. Although it has long been ubiquitous in wiring and motors, the demand for it is rising. An electric vehicle uses about four times as much copper as a conventional car, and even more is needed for the electrical components of renewable power plants and the wires that connect them to the grid. Analysts at Wood Mackenzie, an energy-focused research firm, estimated That offshore wind farms will require 5.5 megatons of the metal in 10 years, mainly for the huge system of cables in generators and for transporting the electrons that the turbines produce to the coast. In recent years, the price of copper has risen sharply and analysts predict a growing shortage of the metal. Goldman Sachs recently stated it “the new oil†
Some companies are already trading it for aluminum where they can. In recent years there has been a shift of billions of dollars in the components of everything from air conditioners to auto parts. Power lines already use aluminum wires because they are both cheap and lightweight, allowing them to be spanned over longer distances. That aluminum is usually in its purest and highly conductive form.